Robert Oster Yellow Boxfish Ink Bottle 50ml

Robert Oster x Melbourne Pen and Stationery Show 2026 - Yellow Boxfish

First described in 1758 by Swedish zoologist, Carl Linnaeus, the Yellow Boxfish (Ostracion cubicus) is found in marine waters across the Indo-Pacific region, including Australia. It can grow up to 45 cm in length, while juveniles are described as “vivid yellow tiny swimming dice with crisp black polka dots”. Their diet consists mainly of algae, sponges, crustaceans, molluscs, worms and small fish. And when stressed or threatened, Yellow Boxfish can secrete a toxic substance (ostracitoxin) through their skin, which can poison nearby fish. Definitely a risky tank mate for your home aquarium.

This year’s ink is quintessentially Robert Oster: Goldilocks flow (not too wet, not too dry, just right), well-behaved, extremely readable (for a yellow), and fantastic for watercolour and art.

Crafted in South Australia, these inks offer smooth flow, subtle shading, and a refined palette suited to both everyday writing and thoughtful creative work.

A drink for your pen.

The Remarkable Robert Oster

Robert Oster is a South Australian colour creator whose inks reflect his passion, creativity, and deep connection to the Australian landscape. His colours are known worldwide for their beautiful shading, reliability, and expressive character on the page.

Robert Oster Signature Inks are handmade in Australia, inspired by the colours of the continent. They are presented in recyclable 50ml PET bottles, manufactured in Australia's first carbon neutral plastics plant. All Robert Oster inks are 100% Australian made and non-toxic, created with care for both the writer and the environment.

Based in South Australia, the same state as Pencraft, Robert Oster’s work continues to inspire writers, artists, and collectors around the world.